Caulking guns have been developed to provide a convenient way to dispense caulking or silicone compounds from cartridges. The cartridges themselves are generally made with a built-in plastic nozzle and provide a sliding plug on the opposite end of the nozzle. Caulking guns generally include a cartridge holder, a plunger with a shaft for pushing the compound in the cartridge, a handle and a trigger mechanism for advancing the plunger. Once the tip of a nozzle is cut, the seal of a cartridge broken using a poker and the cartridge has been placed in the gun, a user squeezes the trigger, advancing the plunger. The plunger in turn pushes the plug and the cartridge extrudes compound. The previous art generally includes a handle and a plunger advancing mechanism towards the back end of the gun. These guns commonly use two coil springs to achieve the tensions necessary on the plunger's parts. Some more sophisticated guns have “no drip” features that release the pressure on the plungers so that compound does not leak from the nozzles when not in use. Current automatic pressure release mechanisms use additional springs and parts to relieve pressure on the cartridge. These mechanisms relieve a plunger's pressure each time a trigger is released. Other guns require a user to depress a tab to release pressure on the cartridges. Some caulking guns include built-in nozzle (snout) cutters. U.S. Pat. No. 6,045,005 describes a circular opening in the side of a handle with a blade on a trigger for cutting the tip of a nozzle. Although a need for simple construction has been noted in the prior art, multiple coil springs have remained common to most caulking guns, some using as many as three springs, cables, ratchets and tabs which a user must activate to operate.
The construction and operation of common caulking guns necessitate a user to hold the gun with both hands for accurate delivery of compound. Usually one hand cradles a cartridge holder and cartridge; the hand's position supports the majority of the gun's weight. The other hand grips a handle and squeezes a trigger. Although this method of operation is adequate for many uses, some applications do not readily allow a user to hold a gun with both hands. In such cases, a user must support the weight of the entire gun with one hand putting added stress on the user's wrist and making precise delivery of compound more difficult. Some situations call for a user to use one hand for bracing his/her own body and only use a gun with the other hand, for example while standing on a ladder. Other situations call for a user to hold an object with one hand and apply compound with a gun in the other hand. In these cases, the user must draw back the hand holding the gun to align a nozzle's tip with the object being held. Operating a common caulking gun in a drawn back position is awkward, potential imprecise and may quickly fatigue a user's wrist.
Although the usual design of caulking guns includes a handle and trigger at the rear, two patents show variations of this arrangement. U.S. Pat. No. 6,640,998 describes a device wherein a cartridge holder slides back against a non-moving plunger. Although this action claims to improve the balance of their invention during use, the entire weight of a full cartridge still hangs in front of a user's hand when a new cartridge is placed in the device. Furthermore, this design has the drawback that as a trigger is squeezed, a nozzle's tip pulls away from the point of contact. This motion requires that a user constantly adjust the gun forward during use. U.S. Pat. No. 4,957,223 describes a handle that is placed towards the front of a caulking gun and uses a complex combination of springs and cables to cause it to function. This design may allow for a better balance at the beginning of use if only one hand holds such a gun, but the device does not allow for the option to operate it by the method of cradling the gun with one hand and gripping the handle with the other hand.